vouch

保证、断言正式

I can vouch that every figure in this report is accurate.

我可以保证这份报告里的每个数字都准确无误。

证明、证实正式

These old letters vouch the authenticity of the painting.

这些旧信件证明了这幅画的真伪。

替…担保、为…作保

She vouched for him when he applied for the job.

他应征那份工作时，她替他担保。

保证、挂保证口语

I can vouch for the quality of the coffee at that little shop.

那家小店的咖啡品质我可以挂保证。